Lecture 10 notes (exam 2 review)

598 ccl2f2l commonsolids wood concrete 088 glass

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Unformatted text preview: heat 1 g of substance by 1 C. SYSTEM Heat transfer out q < 0 Heat transfer in q > 0 ΔE = q + w Work transfer in w > 0 Work transfer out w < 0 Molar heat capacity (cm) • E needed to heat 1 mole of substance by 1 C. Note the same sign convention for q and w 4 2/6/2009 E required to change the T of an object is: Heat required = mass x specific heat x ΔT q = m c ΔT Elements Al(s) C (graphite) Fe(s) Cu(s) Au(s) Compounds NH3(l) H2O(l) C2H5OH(l) (CH2OH)2(l) H2O(s) CCl4(l) 0.598 CCl2F2(l) Common solids wood concrete 0.88 glass granite Heat Capacities or… Heat required = moles x molar heat capacity x ΔT q = n cm ΔT Heat Capacity Example How much energy will be used to heat 500.0 g of iron from 22°C to 55°C? cFe = 0.451 J g‐1 °C‐1. Heat required = mass x specific heat x ΔT q = m c ΔT q = 500.0 g (0.451 J g‐1 °C‐1)(55−22)°C q = 7442 J = +7.4 kJ + sign, E added to the system (the iron) Conservation of Energy and Changes of State When heat...
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This note was uploaded on 03/02/2014 for the course CHEM 101 taught by Professor Multipleprofs during the Spring '07 term at Drexel.

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